The present invention relates to a wiring board, a method of manufacturing the same, a semiconductor device, and an electronic instrument.
Conventionally, a printed wiring board is manufactured by attaching copper foil to, a base material and forming interconnecting lines by etching. This complicates the process and makes it necessary to use an expensive mask for etching. Moreover, a number of pieces of equipment is necessary. A polyimide is generally used as the base material. However, since adhesion between the polyimides is low, it is difficult to manufacture a multilayer substrate.
In recent years, a technology of forming interconnecting lines by ejecting metallic ink onto a surface-treated base material has been developed. In the case of controlling the surface tension of the metallic ink by forming a fluorine film on the base material {fluoroalkylsilane (FAS) treatment} and making the fluorine film porous as the surface treatment, it is difficult to increase adhesion between the interconnecting lines and the base material. Therefore, interlayer separation easily occurs after stacking the base materials, whereby it is difficult to manufacture a highly reliable multilayer substrate. Moreover, since the fluorine films cannot be stacked, a multilayer structure may not be obtained.
As the surface treatment, a method of forming a receiving layer having swelling properties by applying a polyvinyl alcohol to the base material, or a method of forming a (porous) receiving layer having voids by applying aluminum hydroxide to the base material may be employed. However, since the receiving layer tends to contain moisture due to high hygroscopicity, the receiving layer is not suitable as an inner layer or an inner layer of the multilayer substrate. Moreover, it is difficult to increase adhesion between the interconnecting lines and the base material. Since it is difficult to increase adhesion between the interconnecting lines and the base material, interlayer separation easily occurs after stacking the base materials. Therefore, it is difficult to manufacture a highly reliable multilayer substrate.